Young Serial Output Wind Monitor Model 09101 - Manual (Page 5)

Page 4
09101-90(G)
CALIBRATION
Periodic calibration checks are desirable and may be necessary where
the instrument is used in programs which require auditing of sensor
performance. Recalibration may be necessary after some maintenance
operations.
An accurate wind direction calibration requires a Vane Angle Fixture
(Young Model 18112 or equivalent). Details are listed under "VERTICAL
SHAFT BEARING REPLACEMENT STEP 10. ALIGN VANE". The
sensor nose cone must be removed if any adjustment is required.
Wind speed calibration is determined by propeller pitch and the output
characteristics of the transducer. Calibration formulas showing wind
speed vs. propeller rpm are shown on the wiring diagram. Standard
accuracy is ± 0.3 m/s (0.6mph). For greater accuracy, the device must
be individually calibrated in comparison with a wind speed standard.
Contact the factory or your YOUNG supplier to schedule a NIST
(National Institute of Standards & Technology) traceable wind tunnel
calibration in our facility.
To check wind calibration using a signal from the instrument, temporarily
remove the propeller and connect an Anemometer Drive to the propeller
shaft. Apply the appropriate calibration formula to the calibrating motor
rpm and check for the proper value. For example, with the propeller
shaft turning at 3600 rpm adjust an indicator to display 17.6 meters per
second (3600 rpm x 0.00490 m/s/rpm = 17.6 m/s).
Details on checking bearing torque, which affects wind speed and
direction threshold, appear in the following section.
CALIBRATION FORMULAS
Model 09101 Wind Monitor-SE w/08234 Propeller
WIND SPEED vs PROPELLER RPM
m/s = 0.00490 x rpm
knots = 0.00952 x rpm
mph = 0.01096 x rpm
km/h = 0.01764 x rpm
MAINTENANCE
Given proper care, the Wind Monitor should provide years of service.
The only components likely to need replacement due to normal wear
are the precision ball bearings. Only a qualified instrument technician
should perform the replacement. If service facilities are not available,
return the instrument to the company. Refer to the drawings to become
familiar with part names and locations. Maximum torque on all set
screws is 80 oz-in.
FLANGE BEARING REPLACEMENT
If anemometer bearings become noisy or wind speed threshold
increases above an acceptable level, bearings may need replacement.
Check anemometer bearing condition using a Model 18310 Propeller
Torque Disc. Without it, a rough check can be performed by adding
an ordinary paper clip (0.5 gm) to the tip of a propeller blade. Turn the
blade with the paper clip to the "three o'clock" or "nine o'clock" position
and gently release it. Failure to rotate due to the weight of the paper
clip indicates
anemometer bearings need replacement. Repeat this test at different
positions to check full bearing rotation. If needed, bearings are replaced
as follows.
1. REMOVE OLD BEARINGS
a) Unscrew nose cone. Do not lose o-ring seal.
b) Loosen set screw on magnet shaft collar and remove magnet.
c) Slide propeller shaft out of nose cone assembly.
d) Remove front bearing cap which covers front bearing.
e) Remove front and rear bearings from nose cone assembly. Insert
edge of a pocket knife under bearing flange and lift it out.
2. INSTALL NEW BEARINGS
a) Insert new front and rear bearings into nose cone.
b) Replace front bearing cap.
c) Carefully slide propeller shaft thru bearings.
d) Place magnet on propeller shaft allowing 0.5 mm (0.020")
clearance from rear bearing.
e) Tighten set screw on magnet shaft collar. Do not overtighten.
f) Screw nose cone into main housing until o-ring seal is
seated. Be certain threads are properly engaged to avoid
cross-threading.
VERTICAL SHAFT BEARING REPLACEMENT
Vertical shaft bearings are much larger than the propeller shaft
bearings. Ordinarily, these bearings will require replacement less
frequently. In many cases, they may last the life of the sensor. Check
bearing condition using a Model 18331 Vane Torque Gauge. Without
it, a rough check can be performed by holding the instrument with the
vane horizontal and placing a 3 gm weight near the aft edge of the fin.
Failure of the vane to rotate downward indicates the bearings need
replacement.
1. REMOVE MAIN HOUSING
a) Unscrew nose cone from main housing. Retain O-ring for
reuse.
b) Gently push main housing latch.
c) While pushing latch, lift main housing up and remove it from
vertical shaft bearing rotor.
2. UNSOLDER TRANSDUCER WIRES
a) Remove junction box cover.
b) Remove 3 screws holding circuit board.
c) Unsolder transducer wires from circuit board. 9 wires attach at
upper edge of board, 1 wire attaches at bottom near cable
terminals.
3. REMOVE TRANSDUCER ASSEMBLY
a) Loosen 2 set screws at base of transducer assembly and
remove assembly from vertical shaft. Use care to avoid
damaging wires.
4. REMOVE BEARING ROTOR by sliding it upward off vertical shaft.
5. REMOVE OLD BEARINGS AND INSTALL NEW BEARINGS.
When inserting new bearings, be careful not to apply pressure
to bearing shields.
6. REPLACE BEARING ROTOR ON VERTICAL SHAFT
7. REPLACE TRANSDUCER ASSEMBLY. Tighten set screws to 80
oz-in.
8. RECONNECT TRANSDUCER WIRES
a) Gently pull wires through hole in junction box. Needle nose pliers
or a bent wire may be used.
b) Carefully solder wires to circuit board according to
wiring diagram. Observe color code.
c) Secure circuit board in junction box using 3 screws
removed in step 2b. Do not overtighten.